Joint Theory Lunch Seminar / Speaking Skills Talk - Noah Singer

— 1:00pm

Location:
In Person - Gates Hillman 8102

Speaker:
NOAH SINGER, Ph.D. Student, Computer Science Department, Carnegie Mellon University
https://noahsinger.org/

Cosystolic expansion is a generalization of vertex expansion in graphs to "higher dimensions" (i.e., to simplicial complexes). Sparse, efficiently-constructible cosystolic expanders have powered recent breakthroughs in quantum coding and local testability, but these constructions are hard to come by. In this talk, I will present recent joint work with Ryan O'Donnell which analyzes the cosystolic expansion of a certain algebraically-defined complex, called a "B-type Chevalley coset complex", constructed by O’Donnell & Pratt. Our analysis builds on a recent, simpler analysis of a related "A-type complex" due to Kaufman & Oppenheim. These complexes have the advantage that, unlike earlier known complexes due to Lubotzky, Samuels, & Vishne, analyzing their expansion does NOT require any deep mathematical tools. 

I will define all relevant notions, so no prior knowledge of expansion or algebra is required.

Presented as part of the Theory Lunch Seminar
Presented in Partial Fulfillment of the CSD Speaking Skills Requirement

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